Emerging heterostructured C₃N₄ photocatalysts for photocatalytic environmental pollutant elimination and sterilization

Photocatalysis is deemed a highly prominent technology to solve environmental problems such as pollution, CO₂ emission and bacterial contamination. As an important photocatalyst, g-C3N4 has attracted a great amount of attention in environmental remediation owing to its good stability, excellent light response, low cost and environmentally friendly properties. However, the pristine g-C3N4 photocatalyst generally suffers from serious photoinduced charge carrier recombination, poor surface active sites, and insufficient visible light harvesting, thereby leading to unsatisfactory photocatalytic performance. Heterostructured C₃N₄ photocatalysts have recently become a research focus in environmental fields thanks to their fast photoexcited electron-hole pair dissociation, broadened visible light response range, and sufficient photoredox capability. Herein, we critically review the up-to-date developments of heterostructured C₃N₄ photocatalysts in organic pollutant elimination, heavy metal ion reduction, CO₂ conversion and bacterial inactivation. Meanwhile, the strategies for constructing efficient C₃N₄ based heterostructures with enhanced environmental photocatalytic capability are thoroughly described, which should help readers to quickly acquire in-depth knowledge and to inspire new concepts in heterostructure engineering. Finally, the challenges and opportunities in fabricating heterostructured C₃N₄ photocatalysts for large-scale and commercial applications are discussed to give a clear study direction in this field.